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Performance Features

Monitor and test performance characteristics.

Performance Metrics

domguard debug performance

Returns: - Core Web Vitals: LCP, FID, CLS - Timing: DOM load, full load, TTFB - Memory: JS heap size, DOM nodes - Resources: Total size, request count

Example output: 

Performance Metrics
───────────────────
Timing:
  DOM Content Loaded: 245ms
  Full Load: 1.2s
  Time to First Byte: 89ms

Core Web Vitals:
  Largest Contentful Paint: 1.1s
  First Input Delay: 12ms
  Cumulative Layout Shift: 0.05

Memory:
  JS Heap Size: 12.4 MB
  DOM Nodes: 1,247

Resources:
  Total Requests: 45
  Total Size: 2.3 MB

CPU Throttling

Simulate slower CPUs:

# 4x slowdown
domguard debug throttle-cpu 4

# 6x slowdown (mobile-like)
domguard debug throttle-cpu 6

# Disable throttling
domguard debug throttle-cpu --disable

Use cases: - Test on low-end devices - Identify performance bottlenecks - Verify graceful degradation

Network Throttling

Simulate network conditions:

# Presets
domguard debug throttle-network slow-3g   # 500ms latency, 500 Kbps
domguard debug throttle-network 3g        # 100ms latency, 1.5 Mbps
domguard debug throttle-network offline   # No connection

# Disable
domguard debug throttle-network --disable

Custom Throttling

domguard debug throttle-network custom --latency 200 --download 1000 --upload 500

Parameters: - --latency: Round-trip time in ms - --download: Download speed in Kbps - --upload: Upload speed in Kbps

DOM Snapshot

Export full page state:

domguard debug snapshot -o page.html

Captures: - Complete DOM tree - Inline styles - Current state (form values, etc.)

Network Monitoring

# All requests
domguard debug network

# Filter by URL pattern
domguard debug network --filter "api"
domguard debug network --filter ".js"

Shows: - Request URL - Method (GET, POST, etc.) - Status code - Response time - Size

Testing Workflow

  1. Baseline: Capture metrics on fast connection
  2. Throttle: Apply CPU/network throttling
  3. Measure: Compare metrics
  4. Optimize: Fix issues found
  5. Verify: Re-test with throttling
# Baseline
domguard debug performance > baseline.txt

# Throttled test
domguard debug throttle-cpu 4
domguard debug throttle-network 3g
domguard debug performance > throttled.txt

# Cleanup
domguard debug throttle-cpu --disable
domguard debug throttle-network --disable